With an automatic sewing device of this type which is known from U.S. Pat. No. 4,787,324, the needle bar drive, needle oscillating drive and thread take-up lever, on the one hand, and the hook, on the other hand, are adjusted in a like manner during pivoting movements of the rotary housing and hook bearing at the same angle of rotation so that in the rotary housing, on the one hand, and in the hook bearing, on the other hand, the changes in position of the said parts which are triggered in themselves by the pivoting movements are compensated for. With this known embodiment the drive motor and a servomotor act on a differential gear which connects the drive shaft and the adjusting shaft to one another.
In the case of an embodiment according to U.S. Pat. No. 4,787,326 which is of the same generic type this compensating action is brought about by an actuating drive which is connected only to the adjusting shaft and is triggered accordingly by a central control unit.
A further problem with these automatic sewing devices of the type as defined is that it must be possible to produce so-called corner stitches in which case the rotary housing is guided with the needle inserted.
From German published patent application No. 35 38 461 it is known practice to provide a coupling device in a sewing machine having a rotary housing in order to connect the actuating drive to the needle bar drive in order to prevent adjustments of the needle bar resulting from rotary movements of the rotary housing. It is not known how operativeness is to be achieved.